SSC/SCC

Stress corrosion cracking (SCC) is the unexpected failure of normally ductile metals subjected to a tensile stress in a corrosive environment. SCC is highly chemically specific in that certain alloys are likely to undergo SCC only when exposed to certain corrosive environments. Sulfide stress cracking (SSC) is a form of hydrogen embrittlement which is a cathodic cracking mechanism. Susceptible alloys, especially steels, react with hydrogen sulfide, forming metal sulfides and atomic hydrogen, which causes SSC. This section provides access to reports that present test results and evaluate the resistance to SSC/SCC of various materials when exposed to different corrosive environments.

The stress corrosion cracking resistance of alloys SCF-19 and 15-15LC was compared in simulated drilling environments using low strain rate tests, NACE tensile tests and autoclave exposures of DCB and bent beam specimens. Alloy 15-15LC was extremely susceptible to stress corrosion cracking in chloride solutions both with and without H2S. Alloy SCF-19 showed no tendency to stress corrosion crack in any of the environments
tested.

A carburization test and evaluation was performed on selected alloy and coated coupons. Alloys MA 956, HA 214, and the Alonized coupons were screened as the best materials of construction for the given conditions.